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