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