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