Define your styles in the Visualization Styles Editor which is installed along with the CODESYS Development System. Instead of fixed colors or forms, use the identifiers pre-defined in the styles. Within the Visualization Manager you can switch between the available visualization styles and thus change the look and feel of your visualization.
You can find further information on the Visualization Styles Editor in the CODESYS Online Help at https://help.codesys.com/webapp/_visu_editor_style;product=core_visualization