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