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