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