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