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