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