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