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