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