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