Top Blue - I believe this is a mountainous region, not much industry.
Purple - Massive forest area (on the coast at least), also small population and not much industry
Yellow - North Bay, San Francisco, Silicon Valley and Sacramento. Lots of industry, technology and money. Large population as a whole spread out fairly evenly across the region, so lots of medium sized towns and small cities (S.F, Oakland, San Jose, Palo Alto, etc.etc.). Industry includes the big names you know, Google, Facebook, Apple, as well as large research facilities (I believe NASA has a large centre there). Lots of Universities as well.
Red - Some farm-land, mountainous further inland. I believe cattle, cheese, and some fruit orchards.
Green - Great farmland. Grapes and wine region, orchards, lots of cattle land. Moderate populations, towns like San Luis Obispo (great part of California if you haven't visited).
Orange - Massive populations of Los Angeles also medium sized cities of San Diego, Palm Springs/Desert. Massive industry throughout the area serving the population and the industries of Los Angeles. LA is a massive manufacturing hub (clothing, automobiles, the list goes on and on). Massive sea port at Long Beach (there may be others too).