Open it the way it is now from your desktop.

While it is opened in the browser, choose to save it as a "Bookmark".

Save it in the name you would rather have.
Close the browser.

Now delete the desktop shortcut.

Now save this bookmark on the desktop and it should have the name you chose instead of the makers page title.

Also good to know:
The image of the bookmark will be of your actual view of the page when you saved it. So, if there is an icon or title on the page that would give it more distinction on your desktop, zoom to that first before saving.