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