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