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