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