You can graph four channels on one graph by putting your data points into a cluster and then graphing them. Put the average on it's own graph. An example is enclosed, it's version 6.1, but you should be able to open it if you have any higher version.
eewonder
LV 6.1, 8.2, 8.5, 8.6 beta
Fieldpoint
DAQmx
IMAQ Vision