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)(11,13)(12,20)(14,15)(16,18)(17,22)(19,23)(21,24)(25,26,31,30)(27,33,28,32)(29,34,38,37)(35,40,36,39)(2,6)(3,7)(10,15)(11,18)(17,20)(19,24)(25,27,31,28)(26,32,30,33)(29,36,38,35)(34,40,37,39)(1,3)(2,4)(5,7)(6,8)(9,11)(10,16)(12,19)(13,15)(14,18)(17,23)(20,21)(22,24)(25,27,31,28)(26,33,30,32)(29,35,38,36)(34,40,37,39)(1,4)(2,3)(5,8)(6,7)(9,11)(10,16)(12,19)(13,15)(14,18)(17,23)(20,21)(22,24)(25,28,31,27)(26,33,30,32)(29,36,38,35)(34,40,37,39)(9,12,14,22)(10,17,15,20)(11,19,18,24)(13,21,16,23)(25,29,31,38)(26,34,30,37)(27,35,28,36)(32,39,33,40)(9,13,14,16)(10,11,15,18)(12,21,22,23)(17,19,20,24)(25,30,31,26)(27,33,28,32)(29,37,38,34)(35,40,36,39)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.