The reason is quite simple. What you are seeing when you see a colorful sunrise or sunset is the reflection of the sun off of clouds and the various debris in the atmosphere. The trials and turmoil of the day create commotion. The commotion, the activity of both mankind and animals stirs up dust. At night God sends His refreshing dew to settle things down.
People are generally calmer in the morning.
Everything is more peaceful before the problems of the day arise. But sunsets have their light shattered by millions of new dust particles, as well as the clouds, creating much more beauty. Most everyone thinks a baby is beautiful. A baby, like the new day, is fresh and innocent. Then the baby grows.