That doesn't look all that complex graphically. It's just a simple coloured contour map with flat coloured forest features on top, and rivers, lakes, roads, and cities on top of that. Just about any graphics software, vector or raster, could do it fairly easily. It's mostly just a matter of doing the work to put in the details.

it's hard to see the details but the rivers look really improbable. In one place a river starts int he mountains in the middle, flows toward the coast, splits into two rivers half way there, and one of those runs along the middle of an isthmus, and right through the middle of the expanded promontory at the end of it. Rivers run downhill, and splits are short, both in length (they don't go very far) and duration (one fills in or dries out).

The contours also look a bit odd in that the style is clearly that of a precise hypsographic map, but it looks like it's more just an indication of "mountains" vs "not mountains" regardless of actual elevation.