I would color this scene with a vibrancy that emphasizes the personality of the individual in the picture. The blue shirt could be a bright turquoise that stands out from the rest of the image. I would also make the orange pants a warm, sunny orange that is slightly darker than the blue. The black hair should be a deep, rich black. For the green mat, I would use a grassy green and give the LEGO Ninjago set color blocks a bright and vivid tone. The green pillar can be a lighter shade for contrast and the flag a medium blue. Lastly, the white dragon should be an eye-catching white that stands out from the rest of the image. By creating a dynamic and lively image with bold colors, the viewers of the coloring page will be immersed in the scene.