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