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