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)(11,14)(12,16)(13,15)(17,20)(18,21)(19,22)(23,24)(25,26,31,28)(27,34,38,40)(29,33,30,39)(32,36,35,37)(2,5)(6,8)(9,11)(10,14)(12,18)(13,17)(15,20)(16,21)(19,23)(22,24) involution — undirected(11,17)(14,20)(18,23)(21,24)(25,27,29,36,31,38,30,37)(26,32,39,40,28,35,33,34)(1,3,4,7)(2,6,5,8)(10,15)(14,20)(16,22)(21,24)(25,28,31,26)(27,35,38,32)(29,33,30,39)(34,37,40,36)(9,12,13,19)(10,16,15,22)(11,18,17,23)(14,21,20,24)(25,29,31,30)(26,33,28,39)(27,36,38,37)(32,34,35,40)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.