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