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