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