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