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