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