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