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