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