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