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