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