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