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