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