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