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