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