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