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