I don't know if such a diagram exists, but I can explain quite a bit;
In our cars, the waterpump draws in water from the big front water pipe, and then pumps it straight into the block. Therefore the water pipe is the lower pressure point, and the entrance of the water into the block is the high pressure point. This means that coolant will always flow from the hot side to the cold side. I'll break down the flow for each component:
1)Radiator; Coolant flows out of the water pump into the block, then around the cylinders in the block. Then coolant flows through holes in the block deck, and into the cylinder head, then finally flowing out through the thermostat housing mount hole. Coolant flow is regulated by the thermostat, and when it is open, coolant flows out of the thermostat into the upper radiator hose and into the radiator. At this point the coolant is hot. Then the coolant flows down the radiator, is cooled, and flows out of the lower radiator hose. The coolant is at it's coolest point here. The water then flows through the front water pipe and back into the water pump and the process is repeated
2)Heater core: Coolant flows from the port on the thermostat housing, to the heater core, then out, and back into the port on the front water pipe.
3)Throttle body: Coolant flows from the port on the thermostat housing, to the throttle body, then back to the port on the front water pipe. (The nipple tee'd off the pipe for the heater core line)
4)Turbo charger: coolant flow from the thermostat housing port, into the turbo center cartridge, then out through the curved metal line under the turbo and into the front water pipe. What is odd about this situation, is that hot coolant from the thermostat housing is being used to cool the turbo. NOT cool coolant. It is impossible* to do it any other way really.
5)Oil cooler (stock oil/water style): Water flows from the thermostat housing, down the hardline bolted to the front of the block. From there it goes into one port of the oil cooler, then back out and into the nipple in the front water pipe just before it enters the water pump. Again, same situation as the turbo charger. You have hot coolant being used to cool something. Probably another reason the stock oil/water style oil cooler doesn't work that well.
As you can see, you always have a flow that goes from hot to cold. This is due to the way the system is designed. So if you need to run coolant lines to a turbo, use a port or tap the thermostat housing, run it to the turbo, then run the coolant outlet to the front water pipe. You can still use the existing flared fitting port that the stock hard line uses with a custom line with the right fittings.
*It is not really impossible, but if you wanted coolant to flow from cold to hot, you would have to install an independent electric pump to draw from the cooler front pipe, pump it through whatever device, and then exit out to the thermostat housing. You could do it, but a terribly impractical thing if you as me.