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