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