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