After your editing, it became clearer to understand what you need. In this case, I don’t think a Sequence Diagram is the best choice. The sequence diagram models communications (or transitions in your case) over time between the entities involved. Thus, its great use is to represent the logical sequence in which the actions, usually in a specific use case, are performed by all involved (users and components of a system).
From what I understand, your interest is more in representing two things:
- The logical structure of the website, that is, which pages are linked to which other pages
- Properties of certain transitions, for example, if only one profile is able to make/allow a certain transition.
So I agree more with the answer from Mr @rray, on the use of State diagram. On it you can represent each page as a state of your system, and in the transitions add information (even the color, which you yourself suggested) to indicate its properties.
Wireframes, that I mentioned in comments, would be more useful if you want to enter a higher level of detail (but not final - that is, very low level) as to which areas of each page should allow transitions. This helps you not only plan transitions, but also other aspects of user interaction. In this type of diagram, more informal, you can draw the transition arrows from specific areas of a sketch of the screen, for example to indicate if the user should always click in the same region to navigate, in side columns to have access to tools, etc.
Note that although I think that the Sequence Diagram is not the most appropriate one, it does not mean that you cannot use it. You’ll probably just have to do several of them, for each setting navigation. And, even if I answer this question with the best I can infer based on my experience, I still think it’s a little based on opinion, because there really isn’t a more correct answer.
Is your goal to represent the data flow between certain pages, the general structure of the website or what? Because, depending on the goal, you can use one or the other UML diagram. For example, you could use the sequence diagram to represent the planned order in which the user navigates the site (although most commonly it is used for this wireframes - read this other question for more information). If you want to represent the "triggers" that make the pages be switched, maybe the State Diagram is more interesting.
– Luiz Vieira
This "summary" that I found now may be useful to you: http://www.profissionaisti.com.br/2011/07/os-principals-diagrams-da-uml-quicksummary/
– Luiz Vieira
I bet on the activity diagram, because I think that’s what he’s looking for.
– Reginaldo Soares
Could you give an example of want to do? the flow would be conditional? report more details.
– rray
Luiz Vieira, would be type to represent the general structure of the website. Example: on page X the user can have access to such other pages. As it is a web system, depending on the profile of the user it can have access to the page and I can differentiate in the diagram with a color relative to the profile that has access. That’s about it, so I can document the pages and the flow.
– Danilo Tostes