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