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