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