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