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