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)(11,19)(12,15)(13,17)(14,23)(16,21)(18,22)(20,24)(25,26,28,31)(27,33,35,30)(29,38,37,32)(34,39,36,40)(2,5)(6,8)(9,11,13,12)(10,15,17,19)(14,20,22,21)(16,18,24,23)(25,27,28,35)(26,30,31,33)(29,34,37,36)(32,39,38,40)(1,3,4,7)(2,6,5,8)(9,12,13,11)(10,16,17,24)(14,20,22,21)(15,18,19,23)(27,34)(29,37)(30,39)(32,38)(33,40)(35,36)(2,5)(6,8)(10,17)(11,12)(18,23)(20,21)(26,31)(30,33)(32,38)(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.