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