No worries, the example is maybe a bit complicated.
Arduplot will plot multiple data like you want. It doesn't have separate colors, but now they're on my todo list. It will display names on each row, if you provide names. I've modified your code so it'll work with Arduplot and display names.
I forgot to mention that by default Arduplot connects to the serial port at a higher baud rate, so that it takes less time to do all the serial communication. You can use any baud you want, you just have to match the baud that your arduino sends with the baud that Processing receives. Notice I changed your Serial.begin().
I haven't run this code, but once it compiles, you should be able to run Arduplot from Processing and see the plot.
Actually one other note, Arduplot will try to connect to the serial port named with the string "tty.usbmodem" in it. This works on my Mac with a USB connection to the Arduino, but I've not tested this on Windows or Linux yet. If it doesn't connect automatically, find the list of serial ports in the Processing output window when you run Arduplot, then change the setup() function in Arduplot to find the serial port you're using - just replace the string "tty.usbmodem" with something that will match your serial port. I'd love to make that part platform independent and automatic, if anyone else here knows how...
A = analogRead(A0);
B = analogRead(A1);
D = analogRead(A2);
U = analogRead(A3);
C = analogRead(A4);
T = analogRead(A5);