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