Official comment
No, this is not possible. You can only switch between blue and RGB waveforms as Frank pointed out.
Since I run Rekordbox 4.2.1. my waveform is ugly.
Like this:
http://i.imgur.com/H1js7b7.jpg
Before they looks like the ones shown on this page:
http://www.mixingguide.com/energy-levels
I prefer the old ones! Is there a way to change it?
Am I the only one with this problem?
No, this is not possible. You can only switch between blue and RGB waveforms as Frank pointed out.
Post is closed for comments.
Have you tried to switch the waveform view to RGB?
Would look like this:

You have to change the Setting for this
I don't want to have anything else.
Frank
That is not what I mean. See my posted links for the pictures.
Jan,
I just wanted to point you to the different view - just in case. I can't help you with changing the format of the view.
Btw. I don't think the view is ugly - I wouldn't like the minimal view which was there before. So everybody has its own point of view. :-)
Frank