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