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