EPSs have two components: the image itself and the preview. The black and white, jaggy image you see onscreen is the preview. If you have a PostScript-compatible printer, it will read and print out the actual (color) image.
If you do not have a PostScript-compatible printer, consult your software's help documentation to see if your application will accept WMF files. The screen display for this format will more closely resemble the printed output.