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