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)(25,26,30,35,29,34,28,33)(27,36,37,40,38,31,39,32)(1,3,4,8)(2,5,6,7)(9,11)(10,15)(12,16)(13,18)(14,19)(17,22)(20,24)(21,23)(25,27,28,39,29,38,30,37)(26,31,33,40,34,36,35,32)(9,12,13,15)(10,11,16,18)(14,22,21,20)(17,23,24,19)(25,27)(26,32)(28,37)(29,38)(30,39)(31,35)(33,36)(34,40)(2,6)(5,7)(10,16)(11,18)(17,24)(19,23)(25,28,29,30)(26,33,34,35)(27,37,38,39)(31,32,36,40)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.