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