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