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