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