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