Use a concrete grinder to grind and polish your concrete. Use a disc that uses coarse diamond segments embedded in metal for the first round of grinding. Go over the entire floor three or four times using the concrete grinder.
Change the disc in the grinder. Use a disc that has finer diamond shards embedded in a plastic matrix. Go over the floor again to make it look more shiny.
Stain the concrete to make it look more like stone. You can use an acid-resistant brush or a spray to stain the concrete.
Etch lines in the concrete to make it appear that stones have been put together into the floor.