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