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