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