Complex sentence: Tony Heinsbergen, a U.S. designer, who originally chose the color scheme for the interior (ivory, moss green, gold and burgundy) was brought back, fifty years later, for the renovation and was the one to paint the mural on the ceiling dome.
Split into simpler sentences: Tony Heinsbergen, a U.S. designer, who originally chose the color scheme for the interior (ivory, moss green, gold and burgundy) was brought back, fifty years later, for the renovation. He was the one to paint the mural on the ceiling dome.