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