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