Charged electrons flow from the power source along the negative trace (green) thru a resistor to the cathode.
Like excited lemmings they jump the P-N junction emitting light.
Finally, the spent electrons slide along the positive trace (red) to get charged up at the battery.
battery is black
negative trace is green
resistor is blue (conductive thread usually has enough resistance to eliminate a resistor from the sewn eTextile circuit)
diode is yellow
positive trace is red
black dots are connection points