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