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