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