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