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