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