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