Here is a guest bathroom decor idea from Savory Soaps:

When looking for unique ways to store and display decorative bars of soap, fill a clear jar with a wide variety of varieties and hues. Glycerin soap is especially colorful, and it is a great choice when seeking decorative and practical bathroom decor. Consider using two old-fashioned glass  jars of varying heights. The soap inside will beautifully enhance your bathroom hues. 

Make your guest feel welcome with an artfully arranged assortment of bath goodies. Glass jars serve a dual purpose: they are beautiful and elegant, but they also provide storage. They introduce femininity and curve into a space with predominantly straight lines. Pair a few sizes of these jars together, and fill them with decorative soaps, natural sponges, or even bath crystals and salts.
Liquid soap and shampoo cannot be seen when stored in solid colored pumps. Buy tall heavy glass containers with cork lids, and fill them with colorful liquid soap. Various colors can be added to create stripes and designs. Simply add thick colored soap of your choice, and use a wooden skewer to create interesting patterns. Run a wooden skewer along the inside edges to creak streaks, peaks and lines. It will look like liquid sand art. Stick a pump through the center of the cork top, and the decorative container can be used in another unique and practical way.