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