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