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