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