An image of Jessica De Gouw in costume as the Huntress in Arrow has been released via Entertainment Weekly.  It bears little resemblance to the character’s garb in the comics, and that’s intentional, according to the accompanying article.  The look being sought is of "uniforms or outfits," as opposed to costumes, executive producer Andrew Kreisberg told EW.
De Gouw (see "Huntress Cast") is set to appear in two episodes so far; the first will air November 28th.