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