The confusing plethora of PLE/Ns tools is deceptive. Seemingly, for each conceivable purpose and preference, there is a tool that exists or is being built (current week’s topic). This might be true for the communication and collaboration purposes on the social or person-to-person level of connectivism, but not for its conceptual level. And it might be true for linear, hierarchical, tree-shaped, or radial arrangements, but not for networked visualisations.
Just consider such a simple thing as drawing a connection line between two items in your folders on your hard drive, if you want to indicate that there is a vague relationship that cannot be explicated by a subfolder, or a tag name. Most likely you have to switch to a dedicated application which is for Personal Information Management, or for visualization, but not for both, let alone for your files.
There are several screencasts available, showing the same two examples (animals, and conference abstracts) in several variants and program versions, which have different deficits. (For Gnome/ Nautilus, there is even more available now).
The great advantage, IMHO, is the ergonomic combination of visual overview and textual details (see my previous thoughts about this). If you are willing to do without this combination, you might import the terms (file names, labels…) into Cmap Tools (using File > Import > Propositions as text …). But not even this import is reasonably supported, because the terms are initially cluttered on a huddle of concepts hiding each other.
So I am still waiting for something that neither exists nor is being built, but needs to be built.