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