If you have the Genesis framework and a child theme from StudioPress, the default 404 page will display everything that is on your blog.
And by everything I am referring at posts, pages, categories and archives that maybe you don’t want people to see.
This is what I also had on my website and I recently decided that it’s time for me to update this.
So, in order to do that, all you have to do is copy the 404.php file from the genesis directory and edit it the way you want it.
Or easier, just copy the code below, add it to a 404.php file and copy that file in the directory of your child theme. You can see how it looks by wandering a bit on this site.
Be careful not to copy it in the genesis directory, but in the directory of your child theme.
Feel free to customize it the way you want it, as long as you know what you are doing: