It seems likely the same pattern of colours as shown here was carried from 1706 to 1791.
Unfortunately I have no 1757 illustration of these flags and the uniform. Basically the regiment probably had red cuffs with 5 pewter buttons, all else being French off-white until 1761 when it acquired a red waistcoat and collar; the pockets were double vertical ones with 5 pewter buttons.
P.S. I had fairly complicated sinus/polyp/nasal septum surgery on the 4th April and am really only now starting to feel properly recovered so I may be even slower than usual posting further flags etc.. This flag is on account for the moment! One sadly does seem to take much longer to recover from these things as one ages...