I know there are a few camera ready rules. Creatures must be in front of lands, and nothing can be behind lands.
The library can be on either side of the play area (left or right).
The graveyard must be adjacent to the library (player can choose which side of play area both are on).
The exile zone must be near the library/graveyard and must be distinct from the graveyard.
This gets tough when you apply it to things like dredge.
Is there a picture of the "correct layout"?
What exactly does adjacent mean in terms of libary and grave? As in to the left or right of it? Or does above or below work as well?
There are very few hard-and-fast rules about layout. The only official document where there are precise indications is the Magic Tournament Rules in section "2.13 Video coverage", which it seems you read since you nicely summed it up in your OP. Beyond that, as long as you are following the general player communication policy (section 4.1 of the aforementioned Tournament Rules; i.e. you're not hiding or misrepresenting free or derived information), you can pretty much do what you want. All that matters is that your opponent, and a judge if needed, agree that the layout is clear and readable. For a large graveyard, I'd recommend doing several rows or columns, keeping the order clear if you're playing Vintage or Legacy. It can use a large portion of the play area and what would usually be used for the battlefield, there are no rules against that. It is justified because the clarity of that information is paramount when playing with or against a Dredge deck. To sum it up, as long as it's clear what's in the graveyard (and possibly in what order, depending on the format), you'll be just fine.
I'm a former judge (lapsed), who keeps up to date on rules and policy. Keep in mind that judges' answers aren't necessarily more valid than those of people who aren't judges; what matters is we can quote the rules to back up our answers. When in doubt, ask for such quotes.
In sanctioned tournaments at Competitive and Professional rules enforcement level, starting when Dominaria is released (and in Prereleases), mandatory rules for game layout apply to such tournaments (M.T.R. 4.7), not just in games at Professional rules enforcement level with video coverage.
EDIT (Jul. 14, 2018): One rule was renumbered with Core Set 2019.
The library can be on either side of the play area (left or right).
The graveyard must be adjacent to the library (player can choose which side of play area both are on).
The exile zone must be near the library/graveyard and must be distinct from the graveyard.
This gets tough when you apply it to things like dredge.
Is there a picture of the "correct layout"?
What exactly does adjacent mean in terms of libary and grave? As in to the left or right of it? Or does above or below work as well?
Competitive: GW Hatebears - UG Infect - BGW Liege Rhino
Casual: GR Titan Ramp - BR Aggro
WIP: BUW Control Mill
EDIT (Jul. 14, 2018): One rule was renumbered with Core Set 2019.