Yeah I'm reading a nice book from Coecke and Kissinger [1] just issued and am loving it, it's the story of String Diagrams for a wider audience and with all the details fleshed out (not just hinted as in Baez TWFs). Monoidal categories, tensor networks, directed PGMs, quantum computing and even vector space NLP semantics are all particulars seen from this vantage point.

[1] Picturing Quantum Processes, ISBN 1108107710