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