I'd love it if there were other colors of Evening Glory!
There are a few plants that are evening/night bloomers that have color other than white, for instance some Water Lilies are night blooming:
http://www.waterfordgardens.co...
And, Mirabilis jalapa (Four O'clocks):
Four o'Clocks (Mirabilis jalapa) open in late afternoon and stay open at night.
I do agree with Hetty, true nocturnal flowers (those that aren't open in the daytime) are usually pure white or off white to pale yellow in color. The white or light color of the flower reflects the light of the moon and attracts night pollinators such as moths.
