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