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