Visual designs can be presented in different ways, so it always a good idea to know who you will be speaking to. They can be shown with or without annotations depending on the audience. A business stakeholder is less likely to be interested in annotations, but a technical audience might be more interested in the details of the implementation which can serve as the basis for a style sheet.
In my presentation, I might start with the overall concept and how the visual treatments are being applied to unite elements of the page, draw attention to important content and features of the page, and most importantly, enhance the user interaction on your website. The visual design language can include points of balance, symmetry, focal areas, proximity, simplicity, and harmony. I might also address how the visual design fits into the overall brand story, and complements other methods for communicating with customers.
In essence, presenting designs can be a process of talking about the overall viewpoint down to the smallest design detail.