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