The effect you are seeing is simply wind, not a twist.
The reason for the diagonal direction is that the smoke is moving horizontally while the rocket is moving upwards, like this:
How can I be so sure about this? Well, viewing the other side of the rocket is not necessary: If the smoke was indeed ejected sideways, it would continue in the same direction because of inertia, away from the rocket as it curves away. But in the video the smoke follows the curvature of the cylinder, and that can only be explained by the wind causing a lower pressure on the leeward side of the rocket:
We can also confirm this by watching a Saturn launch were the wind speeds were very low, like on the Apollo 8 mission: