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