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