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