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