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