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