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