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