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