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