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