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