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