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