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