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