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