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