This fun and whimsical coloring page depicts Mickey Mouse and his three friends standing in a circle and waving goodbye to somebody who is not in the picture. The red door behind them looks like it could lead to an exciting adventure and could be colored a vibrant red to create a strong contrast to the surrounding colors. For the characters, you could use bright primary colors for each of their outfits and then outline them with a darker color such as black to make them stand out. The sky could be painted in a light blue hue to bring a sense of joy and freedom to the scene. For the background elements, experiment with light pastels and warm hues to provide the scene with an inviting atmosphere. Ultimately, the choice of colors is up to you, so feel free to explore different combinations to make the picture your own.