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