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