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)(25,26,31,30)(27,32,36,40)(28,33,35,37)(29,38,39,34)(1,3,5,4)(2,6,8,7)(9,11,14,21)(10,15,17,18)(12,19,13,20)(16,23,22,24)(25,27,31,36)(26,32,30,40)(28,34,35,38)(29,37,39,33)(1,3,5,4)(2,7,8,6)(9,12,14,13)(10,16,17,22)(11,19,21,20)(15,23,18,24)(25,28)(26,33)(27,29)(30,37)(31,35)(32,38)(34,40)(36,39)(9,13,14,12)(10,16,17,22)(11,20,21,19)(15,23,18,24)(25,26,31,30)(27,32,36,40)(28,37,35,33)(29,34,39,38)(1,4,5,3)(2,7,8,6)(11,21)(15,18)(19,20)(23,24)(25,29,31,39)(26,34,30,38)(27,35,36,28)(32,33,40,37)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.