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