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