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