Thomas Jefferson had his own unique personal style of dress, documented many times by visitors, slaves, friends, acquaintances, and family. Below are selected excerpts from some of these sources describing Jefferson's clothing.
1781-1824. (Isaac Jefferson). "Old Master wore Vaginny cloth and a red waistcoat (all the gentlemen wore red waistcoats in dem days) and small clothes; arter dat he used to wear red breeches, too...He bought a great many clothes from France with im: a coat of blue cloth trimmed with gold lace; cloak trimmed so too. Dar say it weighed fifty pounds. Large buttons on the coat as big as a half a dollar; cloth set in the button; edge shine like gold. In summer he war silk coat, pearl buttons." 
1784. (Thomas Jefferson Randolph) "He (Charles Willson Peale) told me that the first time he ever saw Mr. Jefferson was at Annapolis in company with William Hamilton...They were both as well as himself dressed in scarlet...Mr. Jefferson changed his fashion slowly hence doubtless was the origin of his leather red breeches so known to some in their day..." .
1790. (William Maclay). "Jefferson is a slender man...his clothes seem too small for him..." 
1801-1809.(Margaret Bayard Smith). "If his dress was plain, unstudied and sometimes old-fashioned in its form, it was always of the finest materials..." 
1802. "He was drest, or rather undrest, with an old brown coat, red waistcoat, old corduroy small clothes, much soiled-woolen hose-and slippers without heels."(William Plumer). 
1804. "I found the President dressed better than I ever saw him, at any time when I called him on a morning visit. Though his coat was old & thread bare, his scarlet vest, his corduroy small cloths, & his white cotton hose, were new & clean-but his linnen was much soiled, & his slippers old..." (William Plumer). 
1804. "He wore a blue coat, a thick grey-coloured hairy waistcoat with a red under-waistcoat lapped over it, green velveteen breeches with pearl buttons, yarn stockings and slippers down at the heel..." (Sir Augustus John Foster). 
1806-1822. "He was always very neat in his dress, wore short breeches and bright shoe buckles. When he rod on horseback he had a pair of overalls that he always put on..." (Edmund Bacon). 
1808. "I dined with the President...he was dressed in a pair of dark corduroy breeches-an old fringed dimmity jacket that he bought with him from France which reached down to his hips-a blue cloth coat with metal buttons-worsted stockings nicely drawn up & a clean pair of leather shoes." (Frances Few). 
1814. "...He [Mr. Jefferson] is...dressed in shoes of very thin soft leather with pointed toes and heels ascending in a peak behind, with very short quarters, grey worsted stockings, corduroy small clothes, blue waistcoat and coat, of stiff thick cloth made of the wool of his merinoes and badly manufactured, the buttons of his coat and small clothes of horn, and under waistcoat flannel bound with red velvet." (Francis Calley Gray). 
1815. "His setness, for instance, in wearing very sharp toed shoes, corduroy small-clothes, and red plush waistcoat, which have been laughed at till he might perhaps wisely have dismissed them." (George Ticknor). 
1816. "His dress in color and form, was quaint and old-fashioned, plain and neat-a dark pepper-and-salt coat, cut in the old quaker fashion, with a single row of large metal buttons, knee-breeches, gray-worsted stockings, shoes fastened by large metal buckles." (George Flower). 
1822. "His costume was very singular-his coat was checkered gingham, manufactured in Virginia I suppose. The buttons on it were white metal and nearly the size of a dollar. His Pantaloons were of the same fabric." (Rev. S.A. Bumstead). 
1822. "...wearing a coat of Virginia cloth, surmounting a buff vest and broadcloth pants..." (D.P. Thompson).
1824. "His dress when in the house, is a grey surtout coat, kerseymere stuff waistcoat, with an under one faced with some material of a dingy red. His Pantaloons are very long, loose, & of the same colour as his coat. His stockings are woollen, either white or grey, & his shoes of the kind that bear his name. His whole dress is neglected but not slovenly. He wears a common round hat. He wears on horseback a grey strait bodiced coat, & a spencer of the same material, both fastened with large pearl buttons. When we first saw him he was riding, & in addition to the above, wore round his throat a knit white woolen tipet, in the place of a cravat, & black velvet gaiters under his Pantaloons." (Daniel Webster). 
1826. "His dress was simple, and adapted to his ideas of neatness and comfort. He paid little attention to fashion, wearing what-ever he liked best, and sometimes blending the fashions of several different periods. He wore long waistcoats, when the mode was for very short; white cambric stocks fastened behind with a buckle, when cravats were universal. He adopted the Pantaloon very late in life, because he found it more comfortable and convenient, and cut off his queue for the same reasons. He...did nothing to be in conformity with the fashion of the day." (Ellen R. Coolidge to Henry S. Randall, 1857).
1826. "His simplicity of attire, his plainess of manner was not a flout..."(William H. Thornton).
1826. "Among other small themes of party wit, was Mr. Jefferson's taste in dress, and especially his supposed predilection for red breeches." (George Tucker).