Just put a StyleSettings.cfg file in the TSE folder (that's C:\Users\DarkStar\AppData\Roaming\MeldaProduction\MTexturedStyleEditor here), with contents such as:
<?xml version="1.0" encoding="utf-8"?>
<StyleConfiguration ColorScheme="2" EditorMode="Buttons" EnableUpperCase="0" InvertColors="0"
ResizeX="1" ResizeY="1" Style="Favourite_DS"/>
