Ashkenazim wrap inwards, so both the yud kesher and the loop the strap goes through are near the body of the wearer. Sephardim wrap outwards, so their kesher places the yud near the body and loop on the outside of the bicep. Chasidim also wrap outwards (with the exception of Gur), so they use a Sephardi tefillin knot.
Lubavitch also wraps outwards, but instead of using the Sephardi tefillin knot to do so, they have their own knot with places the yud kesher and the loop near the body like Ashkenazim, while still allowing the wearer to wrap the strap outwards.
I hope this all makes sense, but I expect whoever answers this question will know what I'm saying, because all you need to have is a good knowledge of various minhagim regarding the tefillin.