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