I understand you are concerned with the visual representation of the U-turn maneuver from one lane to another on the same road.
One option is to add a lane between your two target lanes, and setting it's width to 0. This results in an automatically generated maneuver like this:
There is another option if adding a lane to your road would cause other issues. For more manual control of maneuvers, we support changing their paths by using the "Convert to Explicit" button in the Attributes Panel.
This allows you to edit the control points of any maneuver that was either automatically generated or manually created. For example, manually editing the control points can result in a U-turn such as this: