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