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