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