If you mean the short cable that connects the mouse button to the rest of the topcase, that is the one shown in page 9 of the Upper Case Guide, I fear the work is nigh impossible, since the topcase is made of parts melted up in plastic, and the connector under the button is literally out of reach...
If you mean the ribbon cable that connects your top case to the logic board. According to Apple, they would replace your entire top case. According to iFixit, you can buy a used, but in mint condition, ribbon cable, here MacBook Upper Case Cable
However, you must be really careful and check if you've got a brown cable or a silver one. There are pictures on this site, possibly they should be there in every single serious website dealing in refurbished mac parts.
Take carefully apart your current top case cable, look at your broken ribbon cable and buy the one that looks exactly like yours. That's all. The replacement is fairly easy too, but time consuming. Just a matter of removing the top case, peeling an adhesive pad, taking the cable away, putting it somewhere safe and order a replacement.
Check this guide
If you're not curious to know why, you may stop here and return later, when the new cable is in your hands and you've done the replacement.
If not, here's the long story:
The brown ones usually came shipped with the Macbook 1,1 and the first Macbook 2,1, like yours. They came with the "v1" top cases, the earliest ones, the ones built of a less sturdy plastic that were retired because they got easily bent or cracked at the sides with enough wear and tear.
The silver ones ("Foxconn-made", if I'm not mistaken) came later, with the v2 and the later topcases, the ones with the iTunes keys.
They are equally able to be connected to your logic board, but they have a different connector on the top case side.
So, be sure to get exactly a ribbon cable of the same color of the one you've got now. There are photos to help you into choosing carefully.