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