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)(11,16)(12,20)(13,18)(14,15)(17,22)(19,21)(23,24)(29,37)(33,38)(34,39)(36,40)(1,3,5,8)(2,6,4,7)(25,26,30,31)(27,28,32,35)(29,33,37,38)(34,36,39,40)(1,2,5,4)(3,6,8,7)(10,15)(11,18)(17,20)(19,24)(26,31)(28,35)(33,38)(36,40)(1,2,5,4)(3,6,8,7)(9,11,14,18)(10,16,15,13)(12,19,22,24)(17,23,20,21)(25,27,30,32)(26,28,31,35)(29,34,37,39)(33,36,38,40)(9,12,14,22)(10,17,15,20)(11,19,18,24)(13,21,16,23)(25,28)(26,32)(27,31)(29,36)(30,35)(33,39)(34,38)(37,40)(1,4,5,2)(3,7,8,6)(9,13,14,16)(10,18,15,11)(12,21,22,23)(17,24,20,19)(25,29)(26,33)(27,34)(28,36)(30,37)(31,38)(32,39)(35,40)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.