You can use MacVector to create beautiful graphical representations of sequences with control over colors, patterns, fonts, symbols and many other aspects of the layout. The easiest way to get the graphics into another application is to simply choose Edit | Copy, switch to the target application and then choose Edit | Paste. The graphics will be transferred with full vector drawing capability so that you can increase the image size while still retaining high resolution. One particularly useful application for this purpose is Preview, found on all Macintosh computers in the /Applications/Utilities/ folder. With Preview, you can choose File | New From Clipboard to create a new document containing the copied graphics;
From here you can choose File | Export to save the graphics in a number of different file formats.
One alternative approach if using MacVector 13.5 or later is to choose File | Export Tab Contents As… This will let you directly save the graphics in a few different built-in formats.