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