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