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