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