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