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