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