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