Complex sentence: The "Venator"-class ships initially appear with a red and grey Republic color scheme in "Revenge of the Sith"; the "Venator" at the film's end is gray and white, signifying the Empire's rise to power.
Split into simpler sentences: The "Venator"-class ships initially appear with a red and grey Republic color scheme. However towards the end of "Revenge of the Sith" the "Venators" are gray and white, signifying the Empire's rise to power.