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