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