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