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