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