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