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