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