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