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