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