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