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