With these two techniques, you should be able to handle all knots. The knot is now outlined. If you prefer solid lines, click on the double-headed arrow by the color selector in the toolbar. Adjust stroke weight to taste. If the knot is made of multiple lines, try selecting all the segments of a line, grouping them, and then setting a color.
Gradients can also create some nice effects.
Try setting a line to a gradient fill. Then try making a compound path from the line's pieces and filling with a gradient again. Finally, select everything and group it. Now you have a knot that's one complete object. Don't forget to save your work.