One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,7,8,5)(9,10)(11,17)(12,16)(13,15)(14,18)(19,23)(20,22)(21,24)(1,3,4,8)(2,5,6,7)(9,10)(11,14)(12,16)(13,15)(17,18)(19,21)(20,22)(23,24)(25,26)(27,33)(28,32)(29,31)(30,35)(34,40)(36,38)(37,39)(9,11)(10,14)(12,19)(13,18)(15,17)(16,21)(20,24)(22,23)(25,27,29,35)(26,30,31,33)(28,36,37,34)(32,40,39,38)(10,15)(14,17)(16,22)(21,23)(26,31)(30,33)(32,39)(38,40) involution — undirected(11,18)(14,17)(19,24)(21,23)(25,28,29,37)(26,32,31,39)(27,34,35,36)(30,38,33,40)(9,12,13,20)(10,16,15,22)(11,19,18,24)(14,21,17,23)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.