The diagram you attached clearly states "electron flow" as going from minus to plus, so it's correct. Did you notice the current source on the very left of your drawing? It's a circle with an arrow showing current direction which is the OPPOSITE direction (that is, going from plus to minus) as electron flow.
That's the convention for schematic symbols including transistors: "current flow" is defined as plus to minus, even though we know electron flow is the opposite. "Current flow" is a mythical entity that flows the reverse of electrons. I read someplace that Ben Franklin was the guy who first declared which way current flowed way back when..... and with a 50-50 chance of being right, he got it wrong.
maybe that's just a legend, but I remember reading it.