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