It's mentioned in the article that Go has a very fast compilation time and the same can be said of D language. The reason they are fast to compile because the languages' authors design the languages to be compiler friendly unlike C++. One of the main tricks to being fast to compile is by avoiding symbols look-up table.
For one of the feasible solutions, perhaps Petri net is better than graph. It is a generic state machine mechanism and here are a few examples of having a compiler design using Petri Net approach[1][2].
[1] ZINC: a compiler for “any language”-coloured Petri nets, https://www.ibisc.univ-evry.fr/~fpommereau/publis/2018-01-01...
[2] Model, Design, and Evaluation of a Compiler for a Parallel Processing Environment, https://ieeexplore.ieee.org/document/1702471