Um, are you suggesting that there are twenty Shards of Adonalsium, or twenty types of Shardblades, or what?
This image actually represents neither: it represents the ten orders of Knights Radiant and the ten Surges. You see, each order of Radiants (the bigger symbols on that picture) utilize two of the Surges (the smaller circles). So, the lines there are connecting Orders to which particular Surges--abilities--they use. A few Surges are Gravity, Pressure, and Transformation.
So basically this image relates to things on Roshar, not general cosmere.
All evidence suggests that there are sixteen Shards of Adonalsium. (For example: "Three of sixteen ruled, but now the Broken One reigns." This definitely refers to Shards.)
EDIT: Stroniax, please do not double post. The edit button exists for a reason, thanks