One vertex per element, one color per generator, with an edge from x to x·s.
(5,6,9,15,11,17,32,18)(7,19,21,40,23,49,24,12)(8,25,27,60,29,51,30,46)(10,33,31,16,36,50,63,37)(13,41,43,59,39,34,52,22)(14,28,45,35,47,64,48,65)(20,54,26,61,56,68,57,42)(38,62,44,67,66,58,53,55)(1,2)(3,4)(5,7,11,23)(6,12,17,40)(8,26,29,57)(9,24,32,21)(10,22,36,59)(13,16,39,37)(14,44,47,53)(15,49,18,19)(20,30,56,27)(25,54,51,68)(28,62,64,58)(31,34,63,41)(33,52,50,43)(35,55,65,67)(38,48,66,45)(42,46,61,60)(2,4)(5,7)(6,13)(8,20)(9,21)(10,34)(11,23)(12,37)(14,42)(15,43)(16,40)(17,39)(18,52)(19,33)(22,31)(24,32)(25,38)(26,27)(28,58)(29,56)(30,57)(35,55)(36,41)(44,60)(45,54)(46,53)(47,61)(48,68)(49,50)(51,66)(59,63)(62,64)(65,67) involution — undirected(5,8,11,29)(6,14,17,47)(7,20,23,56)(9,30,32,27)(10,35,36,65)(12,38,40,66)(13,42,39,61)(15,48,18,45)(16,51,37,25)(19,53,49,44)(21,57,24,26)(22,58,59,62)(28,63,64,31)(33,46,50,60)(34,55,41,67)(43,68,52,54)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.