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