Google Apps script for adding a menu and action to a Google Spreadsheet attached to a Google Form. When used will generate edit links in the first empty column. Provides for a nice GUI for editing form values, especially helpful for forms with drop down selections where editing in the spreadsheet itself is unsatisfactory.

GenerateEditLinks.gs

function onOpen() {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var menuEntries = [ {name: "Generate Edit Links", functionName: "genEditLinks"}];
  ss.addMenu("Generate Edit Links", menuEntries);
}

function genEditLinks() {
  var spreadsheet = SpreadsheetApp.getActiveSpreadsheet();
  var urlSplit = spreadsheet.getFormUrl().split('/');
  var formId = urlSplit[urlSplit.length - 2];
  var form = FormApp.openById(formId);
  var sheet = spreadsheet.getActiveSheet();

  var data = sheet.getDataRange().getValues();
  var urlCol = sheet.getLastColumn();
  
  if (sheet.getRange(1, urlCol).getValue() != '') {
    urlCol++;
  }
  
  var responses = form.getResponses();
  var timestamps = [], urls = [], resultUrls = [], hyperlink;
  
  for (var i = 0; i < responses.length; i++) {
    hyperlink = '=hyperlink("' + responses[i].getEditResponseUrl() + '", "Edit Form")'
    timestamps.push(responses[i].getTimestamp().setMilliseconds(0));
    urls.push(hyperlink);
  }
  for (var j = 1; j < data.length; j++) {
    // If the timestamps from the grid data match the timestamp of the response
    // otherwise, this row has been deleted and we don't need its URL
    resultUrls.push([data[j][0] ? urls[timestamps.indexOf(data[j][0].setMilliseconds(0))] : '']);
  }
  sheet.getRange(2, urlCol, resultUrls.length).setValues(resultUrls);  

}