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