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