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