If you are wanting the concrete only and don't want other flooring materials, I would Definitely sweep, mop with a good floor cleaner to remove all the dirt and grime and then mop again with fresh water and let it air dry. I would buy exterior concrete paint which is often used for patios and garages. The swirls will show up but you can minimize this by sponge painting a second color. You can paint a lighter color on the floor as a base and once dry just lightly sponge the darker shade into the lighter giving a two tone look and then add an awesome large area rug