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