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