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