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