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