There is simply no way of accurately representing a black body radiation in a simple blue/amber representation...it would behoove you to ignore the graphic represent and try to understand the theory. OK?
Jeff is correct in that the graphic is an oversimplification, but it has proven useful in practice. A very similar graphic is shown in this
link (scroll down about a third way) and is cited as coming from Kodak and MIT and is thus authoritative. A similar representation is shown here
along with the spectral power distribution (SPD) of the sun as seen from above the earth's atmosphere. The sun is not a perfect black body radiator and the SPD of sunlight is further modified by water vapor and pollutants in the atmosphere. On the other hand, a tungsten lamp closely approximates a black body radiator.
The color temperatures shown in the graphic are correlated color temperatures. See the first link or Wikipedia for further explanation.