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