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