From Cosmic microwave background page on wikipedia, The image is a mollweide projection of the temperature variations over the celestial sphere.The average temperature is 2.725 Kelvin degrees above absolute zero (absolute zero is equivalent to -273.15 ºC or -459 ºF), and the colors represent the tiny temperature fluctuations, as in a weather map. Red regions are warmer and blue regions are colder by about 0.0002 degrees. This map is the ILC (Internal Linear Combination) map, which attempts to subtract out noise from the galaxy and other sources. The technique is of uncertain reliability, especially on smaller scales, so other maps are typically used for detailed scientific analysis.
That being said, if space is warped in 4 dimensions, there is no edge to the universe, just as there is no edge to the surface of a balloon.