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