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