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