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