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