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