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