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