Unfortunately, I cannot directly generate a visual sentence diagram. I am a text-based AI and do not have the capability to create images or diagrams. To generate a sentence diagram for "This was strange and unexpected intelligence; what could it mean?", you will need to use a Sentence Diagram Generator tool. Many such tools are available online; some are interactive websites, while others may be downloadable software. Search online for "sentence diagram generator" to find one that suits your needs. These tools typically allow you to input a sentence and will then generate a visual representation of its grammatical structure.