Hapalochlaena lunulata is day active and colorful. I would not consider them "smart" and while they are at times interactive, I doubt that you would want that kind of contact.
Seriously, I've collected probably 15 or so species of pygmy and the only one that completely meets your criteria is Octopus chierchiae from the Pacific coast of Central America and Mexico.
Octopus wolfi is not particularly colorful, although with its stubby arms, mottled brown or cream color and frequent unilateral color displays, I consider it an interesting beast. The sexual dimorphism in sucker morphology (males have fringed distal suckers) is also a curiosity. THey aren't exactly day active, but do forage and certainly mate during the day. I would not consider them very "interactive".
At a slightly larger size, Octopus aculeatus fits your criteria, but this animal is of a size that you would probably want at least a 40-50 gal tank.
Roy