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)(11,16)(17,18,20,22)(19,21,23,24)(26,27)(29,37)(31,33)(35,40)(1,2)(3,7)(4,6)(5,8)(9,10)(11,15)(12,16)(13,14)(19,23)(21,24)(25,26,30,27)(28,31,36,33)(29,32,37,34)(35,38,40,39)(3,8)(5,7)(10,14)(12,15)(17,19,20,23)(18,21,22,24)(25,27,30,26)(28,31,36,33)(29,32,37,34)(35,39,40,38)(1,2)(3,5)(4,6)(7,8)(9,11)(10,15)(12,14)(13,16)(17,18)(19,21)(20,22)(23,24)(25,28)(26,31)(27,33)(29,35)(30,36)(32,38)(34,39)(37,40) involution — undirected(1,3,4,8)(2,5,6,7)(9,12,13,15)(10,11,14,16)(17,18)(19,21)(20,22)(23,24)(25,29)(26,32)(27,34)(28,35)(30,37)(31,38)(33,39)(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.