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