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