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