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