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