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