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