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