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