You can have your plans print the same colors you have on screen or leave them the way they are.
To have WYSIWYG you need to change your pen settings.
In Wall Definition change your pen colors to what you will see on screen.
To change print colors, go to;
File >System Options > Pen Setup. Click on Configure Print Pen Styles
Set your colors and line weights.
Version 14 to see line weights on screen go to;
Options > Visible Items
At bottom of window check the Display Print Pen Style
You can also print out what your line weights look like by drawing a line and change the pen for all 16 line weights. That is pen 1, pen 2, pen 3..
You won't see much if any difference on screen (when drawing) till you reach at least .40 pen weight.
I have set up different colors for my existing, new, remove walls