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