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