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