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