Create an image of a giant octopus painted on the side of a double-decker bus, swimming through a graffiti-filled underwater cityscape filled with colorful fish and coral.

A vivid mural of a colossal octopus sprawls across the side of a classic red double-decker bus, its graceful tentacles woven with intricate detail. The bus seems to be effortlessly gliding through an extravagant cityscape drowning in vibrant graffiti, each piece of street art telling its own unique tale. The submerged city is teeming with a myriad of bright fish, each species more colorful than the last. In the midst of this underwater metropolis, the viewer discovers lush coral structures, their vibrant hues mirroring the graffiti above. Sunlight pierces the surface, casting a sparkling glow across this subaquatic wonderland.