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