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