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