Think of the song in a really dirty way. It's about sex. The vagina is the "valley of making". The men and women in the creamy white suits represent sperm; They're men and women because each has either an X or Y chromosome, or the women are eggs, and they all carry different genes, hence the many colours. In French, an orgasm can be called a "petit mort" or little death. I'm also seeing some suggestions of birth, with the "drew the curtain back on the morning", and "Labor, Ardor, Languor".
It's post-suicide, and whoever has done it is drifting off to the afterlife and seeing all these wonderfully pleasant things.
Two theories: