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