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