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