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