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