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