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