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