When we say Iran, we image a picture of a country where women are dressed in clothes that completely cover their arms, neck and back. The culture was not the same in 70s before the Islamic Revoluion.
The country was secular, there was cultural freedom and women were given the freedom to wear whatever they like. The women then were more fashion oriented and dressed up following modern approach in western attire. You can check out the old magazines of that time to see how women dressed up back then. However, the women still are stylish and can be seen wearing colorful and stylish outfits.