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