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