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