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)(11,14)(12,15)(13,16)(17,24)(18,22)(19,21)(20,23)(25,26)(27,33)(28,31)(29,38)(30,35)(32,37)(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.