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