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)(11,17,18,14)(12,20,21,15)(19,22,24,23)(25,26,29,32)(27,33,34,30)(28,36,37,31)(35,38,40,39)(2,5)(6,8)(27,34)(30,33)(35,40)(38,39) involution — undirected(9,11)(10,14)(12,19)(13,18)(15,22)(16,17)(20,23)(21,24)(25,27,29,34)(26,30,32,33)(28,35,37,40)(31,38,36,39)(11,18)(14,17)(19,24)(22,23)(25,28,29,37)(26,31,32,36)(27,35,34,40)(30,38,33,39)(9,12,13,21)(10,15,16,20)(11,19,18,24)(14,22,17,23)(26,32)(27,34)(31,36)(35,40)(1,3,4,7)(2,6,5,8)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.