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