You have opened a project. Options > Settings > Projects > "Project name" > Devices > Cable (Cable connections). Select the General tab.
This tab is used to define whether autoconnecting lines are colored by potential or by cable.
Overview of the main dialog elements:
Representation of the autoconnecting line:
Select the Cable-oriented option if you want the autoconnecting lines to be colored by cable, or the Potential-oriented option if you want them to be colored by potential.