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