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