The simplest way:
Download the STL file, run it through your slicer and print. The STL provided goes from 'skip 2 holes' to 'skip 12 holes' and will print with a bed area of
15cm x 15cm (6 inch x 6 inch).
Download the OpenSCAD source file, adjust the parameters at the top of the file, generate the STL, run it through your slicer and print. The parameters are fairly self explanatory (for more details go to http://thegaragelab.com/posts/breadboard-wire-bender-tool.html).