There is not a supported feature of the Power Gallery that will create a page like this for you, it would need to be created manually.
The idea is that you can query the db with a recordset like this:
ORDER BY id ASC
This recordset will contain all of the galleries that you have. You would then need to a link for each way a gallery can be viewed, there will be 12 links total. You will have the six types of gallery and the light and dark for each of those. These links will go to a page that you have a PowerGallery code block on that might look like this:
$pg_id = $_GET['pg_id'];
$pg_theme = $_GET['theme'];
include('C:/Websites/PowerGallery/galleries/' . $_GET['type'] . '/index.php');
You will need to add parameters to each of the twelve links to pass along these values for the id, theme, and type. This is kind of a high level overview, how the links look in the end will depend on your page names and locations. Once the links are all crafted you would apply a repeat region around them so that you have a set of links for each gallery you have.
Please post back with any additional questions that you have about any part of this.