One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(5,6,10,15,11,16,18,34)(7,17,29,32,21,12,22,41)(8,13,25,36,26,37,44,58)(9,14,38,59,27,39,28,40)(19,42,51,33,46,30,23,49)(20,31,47,56,48,43,54,63)(24,35,60,68,52,61,53,62)(45,55,50,57,65,64,67,66)(1,2,4,3)(5,7,18,22,11,21,10,29)(6,12,15,41,16,17,34,32)(8,23,44,46,26,51,25,19)(9,20,38,47,27,48,28,54)(13,33,36,30,37,49,58,42)(14,31,40,63,39,43,59,56)(24,50,60,65,52,67,53,45)(35,57,62,55,61,66,68,64)(1,2,4,3)(5,8,18,44,11,26,10,25)(6,13,34,58,16,37,15,36)(7,19,29,51,21,46,22,23)(9,24,38,60,27,52,28,53)(12,30,41,49,17,42,32,33)(14,35,59,68,39,61,40,62)(20,45,54,67,48,65,47,50)(31,55,63,66,43,64,56,57)(1,3,4,2)(5,9)(6,14)(7,20)(8,24)(10,28)(11,27)(12,31)(13,35)(15,40)(16,39)(17,43)(18,38)(19,45)(21,48)(22,47)(23,50)(25,53)(26,52)(29,54)(30,55)(32,56)(33,57)(34,59)(36,62)(37,61)(41,63)(42,64)(44,60)(46,65)(49,66)(51,67)(58,68)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.