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