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