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