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