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