Answer: Sir Isaac Newton invented the first color wheel. While studying white light reflecting off prisms, he noticed that the light reflected a spectrum of colors. Noting down the different hues, he believed the rainbow of colors shared a harmonious relationship.
To create the mood that your client want, you will need to EMPHASIZE THE EXISTING QUALITIES OF THE ROOM SINCE THEY SUIT THE DECORATING REQUIREMENTS. From the description given in the question, it can be seen that the available room already has the qualities that are desired by the client, all that the artist needs to do is to amplify the qualities of the room by decorating it to the taste of the client.