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