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