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