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