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