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