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