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