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