Referring to the quote from the movie "Cars," it is believed to be coined off of Muhammad Ali's "Float like a butterfly, sting like a bee."
But in the movie it seems to be a variation of Ali's quote but in "racing terms," since both Cadillac and Beemer (BMW) are both real life car manufacturers.
"Float like a Cadillac, sting like a beemer."
- Doc Hudson and Lightning Mcqueen
"Float like a butterfly, sting like a bee"
- Muhammad Ali
"He's driving so smooth and fast, it's like he's floating like a Cadillac and stinging like a Beemer"