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