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