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)(11,19)(12,21)(13,20)(14,18)(15,17)(16,22)(23,24)(25,26)(27,33)(28,30)(29,37)(31,35)(32,36)(34,40)(38,39) involution — undirected(1,3,4,8)(2,5,6,7)(9,11)(10,12)(13,16)(14,21)(15,24)(17,22)(18,19)(20,23)(26,30)(29,36)(33,40)(35,38)(9,12,14,19)(10,16,18,24)(11,20,21,17)(13,23,15,22)(25,27,28,34)(26,31,30,39)(29,38,36,35)(32,40,37,33)(2,6)(5,7)(9,13,14,15)(10,17,18,20)(11,16,21,24)(12,22,19,23)(26,30)(27,34)(32,37)(35,38)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.