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