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