I have cpanel installed on my server, but the thing is I'm just using it to store files, so I don't want to have to attach any domains to it.
How can I make it so I can just have everything at http://serverip/
Take a look at /etc/httpd/conf/httpd.conf . The first VirtualHost entry there is the default one, which is where you should upload files if you want them to be visible using just the IP.
CPanel is a lot of overhead if you are just using this to store files, you could easily get away with a plain linux box + any web server.