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