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