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