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