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