How to work with google diffs in C#?

Question

  listBox1.Items.Clear();
        var dmp = new diff_match_patch();
        var diffs = dmp.diff_main(richTextBox1.Text, richTextBox2.Text, true);

        foreach (var i in diffs)
        {
            listBox1.Items.Add(i);
            ;               
        }

I got this working, it compares two strings and writes out insertions, deletions etc., but it's not really readable. I would like to get something like that:

Could you please help me with, or at least how to begin with this one?