Hmmm... I see that as a very, very long sash wrapped & tied, not separate pieces. Although upon closer inspection it needs two pieces.
Try this, see how close it gets:
Get a piece of white fabric with nice drape 2 yards/ meters long. A rayon dress fabric would be nice. Cut it into 8"-10" wide strips (get at least four out of your yardage width) and do lapped seams end to end to get two roughly 8 yard long sashes. It's a lot of hemming, take breaks.
Then try tying it on.
I'd start with the middle of the sash at your natural waist in the front, right on your belly button.
Wrap to the back and do a single overhand knot (the first step in tying a shoelace).
Pull the tails toward the front, maybe tucking them through the waist portion once to allow the downward drape to start at the sides.
Criss-cross in front, allowing them to drape low.
Pass the tails back up to the back.
Tie a VERY loose square knot. In fabric, it can be manipulated to look like what is seen there (and part of how it got it's name).
Take your second sash and tie it like a shoelace with only one loop to one side at the hip, pass across and tie to the other hip area.
It won't look exactly like it's drawn, but it will be beautiful and dynamic in real fabrics.