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