You can use this module with the following in your ~/.xmonad/xmonad.hs:

 import XMonad.Layout.Spiral

Then edit your layoutHook by adding the Spiral layout:

 myLayouts =  spiral (6/7) ||| etc..
 main = xmonad defaultConfig { layoutHook = myLayouts }

For more detailed instructions on editing the layoutHook see:

XMonad.Doc.Extending

A spiral layout. The parameter controls the size ratio between successive windows in the spiral. Sensible values range from 0 up to the aspect ratio of your monitor (often 4/3).

By default, the spiral is counterclockwise, starting to the east. See also spiralWithDir.