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