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