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