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