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