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