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