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