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