Building a house cannot be done without a proper plan and a structure. The same applies to websites. Site maps are a visual representation of your site's organization, that display how everything is linked together.

Usually a simple site map of a basic site will look a lot like an organizational chart, a general view of the site's structure. 

But if you site is designed with intuitive navigation for the user, why bother with building a site map?

The answer is that they are extremely useful for those who creating the site. First, the developers will use the site map to validate assumptions about functionalities they are working on while developing the site.

Business owners will use it as a reference to confirm the goals and content of the site.

Visual designers will need it to plan out a design that can scale throughout the site. 

And last but not least, you, as a UX designer, you will go back and forth checking the site map while designing the wireframes dividing the navigation accordingly, bewteen primary and secondary navigation (the main navigation bars versus the secondary “Contact us, About us, Privacy policy, Terms of use, Site map, Links” parts of the page).

How do you create a site map?

Whatever works for you! You already did some card sorting, so you know how the information is going to be organized. You can use whatever method or tools that you like, but remember to respect the following rules: 

1. Always number every page (see the main image above). 
    
2. Create proper connectors on your map. As they say, cleanliness is next to Godliness. Bad connections create an ugly sitemap, so it’s best to show that you are keen on even the smallest details.
    
3. Create good text alignment. The map has to be visually appealing.
    
4. Have good alignment of the pages or nodes on your diagram. I wouldn't worry too much about this, as some applications align everything automatically and properly, but keep an eye on it, just in case. 

The nature of sites and applications are changing, and so are site maps. It's an evolving art that has retained the same core spirit over time, but with some changes. Data is being handled differently nowadays, and design wise, sites are changing; it may not be drastic, but they are changing.

Site maps are still useful for communicating a site's structure and navigation (through "task flows"), but just like everything in this field, it’s always evolving. I’ll keep you up to date though; keep on reading!