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