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