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