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