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