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)(8,24,29,58)(9,16,31,48)(10,15,33,46)(11,34,30,17)(14,41,45,26)(19,50,54,67)(20,55,32,38)(21,47,51,37)(22,49,35,39)(25,56,59,68)(27,57,61,44)(28,62,60,43)(36,63,65,52)(42,64,66,53)(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)(19,27)(20,33)(22,30)(24,56)(26,53)(28,63)(29,59)(31,51)(34,39)(36,43)(37,48)(41,64)(44,67)(45,66)(46,55)(50,57)(52,60)(54,61)(58,68)(62,65)(5,8,10,27,11,28,31,41,12,29,33,61,30,60,9,26)(6,14,16,43,17,44,46,58,18,45,48,62,34,57,15,24)(7,19,51,59,22,53,32,63,23,54,21,25,35,64,20,52)(13,36,55,66,39,56,47,67,40,65,38,42,49,68,37,50)(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.