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