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)(27,33)(28,36)(29,32)(30,35)(31,37)(34,39)(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)(27,34)(28,37)(31,36)(33,39)(9,12,14,11,15,20,13,21)(10,16,17,22,19,23,18,24)(25,27,28,35,29,34,37,40)(26,30,31,33,32,38,36,39)(2,6)(5,7)(9,13,15,14)(10,17,19,18)(11,12,21,20)(16,22,23,24)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.