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)(11,17)(12,14)(13,21)(15,20)(16,18)(19,23)(22,24)(25,26,28,31)(27,33,35,30)(29,38,37,32)(34,39,36,40)(2,5)(6,7)(10,14)(15,22)(16,21)(17,23)(25,27)(26,30)(28,35)(29,34)(31,33)(32,39)(36,37)(38,40) involution — undirected(9,11,18,24,12,19,13,20)(10,15,21,23,14,22,16,17)(27,34,35,36)(30,39,33,40)(1,3,4,8)(2,6,5,7)(10,14)(15,22)(16,21)(17,23)(26,31)(30,33)(32,38)(39,40)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.