The sprites in the game are usually inaccurate for no reason even in Rondo of Blood, Richter's hair in illustration or cutscene are shorter while his game sprite has a longer hair, somewhat a homage to the previous Belmont sprites like Simon, Trevor and Christopher. Even Maria's game sprite in Rondo of Blood is innacurate, she has a blue ribbon and a white short sleeve as oppose to red ribbon and pink short sleeve from her illustration or cutscene.
Possibly the designer is probably lazy to replace the pink color, looks like a half-assed redesign from Rondo of Blood version. Same thing as Richter in SOTN which still looks the same from Rondo of Blood with some minor changes and he looks nothing from Ayami Kojima's redesign.