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