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