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