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