Guideline 6.6.2 of the Tactile Graphics guidelines gives only a few remarks about Cartesian Graphs. 22.214.171.124 says that numeric indicators should not precede the numbers on the x-axis and y-axis lines. (I don't know if the supplement of braille examples is available yet.)
My recommendation is to include only what is in the print copy, that is, braille the 10s and the -10s, aligning as you would in a number line only without the numeric indicators. Because the graph is isolated in this example (there is only one of them on this page) I would reproduce exactly what you see in print.
As a side comment, having brailled hundreds of these graphs, within a chapter full of Cartesian graphs I do not feel that it is necessary to reproduce all 400 dots for every single graph. The first graph should be shown in full, but following graphs in the chapter can be simplified. You can tell the reader in a transcriber's note that all squares or dots or tic marks on the x- and y-axis scale are "one unit" which eliminates the need to constantly show the 10s and -10s (which often get in the way of the graph line). You also need not show the entirely empty quadrants, as long as you include the origin and a few units above/below/left/right of it for orientation within the plane. I would apply these suggestions only to high school and levels above that.
**IF THE SCALE CHANGES you must be very sure to show a full graph grid and include all labels. A TN telling the reader that the scale has changed in the next graph is very important.
As always, I welcome comments to the contrary.