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