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