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