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