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