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