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