The color matching functions (in the first chart) tell you in absolute quantities how much light from each primary is needed to match a reference light. The scalar quantities are known as tristimulus values.
The chromaticity coordinates are the color matching functions normalized so that the sum of each value adds up to 1.
This gives you a better way to visualize the relative quantities of lights involved in a color match.
RGB = tristimulus values (first chart)
rgb = chromaticity coordinates (second chart)
r = R/(R+G+B)
g = G/(R+G+B)
b = B/(R+G+B)
for example the chromaticity coordinates show you that to match 380nm light you need much more blue primary light than red primary light.
The color matching functions show you that despite needing more blue than red, in absolute terms you need very little of either because the eye is not very sensitive to 380nm light.
In order to visualize the color matching functions you need a 3D graph (each primary is a dimension). The normalized chromaticity coordinates allow you to create a 2D visualization (the 3rd dimension can be derived from the other 2 since they all sum to 1).
The 2D plot is called a Chromaticity diagram, here's the diagram for the above rgb chromaticity coordiantes.