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