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