Williams says she was only hit by the soda.
Footage of the altercation, filmed by another customer inside the restaurant, only shows what happened after Williams was allegedly hit with the drink.
A witness told WJXT: "The customer took her whole cup of Coke and threw it at the manager. The manager came out from behind the counter, confronted the lady, kind of butted her up against the counter, slapped her face, knocked her glasses off."
Meanwhile, Williams has called the incident "embarrasing" and wishes it had never happened.
"At that moment, no one can tell you what it feels like at that moment," she told WJXT.
"It was more-so embarrassment, because I was still nice to her. I gave it my all and I stayed professional, even with her calling me every name in the book."
McDonald's has confirmed that the owner/operator of that restaurant, Debbie Moreland, is currently looking into the incident.
"I do not condone the behaviour depicted in this video. We are currently investigating this matter," Moreland said.