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