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