Looking at the chart, and reading their descriptions, it does look like they are following insustry-standard codes for what they mention at least. The only difference is that they are painting the whole pipe, not just marking by bands.
Picture 5 (http://www.google.com/about/datacenters/gallery/#/all/5)
Caption: "The blue pipes supply cold water and the red pipes return the warm water back to be cooled."
The suggested markings ("Chilled Water Supply" and "High-Temp Hot Water Return") match the colors shown. You can also see labels on the pipes over on the right of the picture fitting the description.
Picture 9 (http://www.google.com/about/datacenters/gallery/#/all/9)
Caption: "The bright pink pipe in this photo transfers water from the row of chillers (the green units on the left) to a outside cooling tower."
The suggested markings state that this color should be used for condensate / steam, which seems to match the description. Likewise, you can see a label to the left on the green pipe stating "Chiller Condenser Water Supply". The suggested markings indicate this would also match. The label on the yellow pipe is "Chiller Condenser Water Return", which might possibly fit with "Low-Temp Hot Water Return" as suggested on the linked page.
So, it looks like they are following standard conventions as close as possible. Keep in mind this tour isn't just for people who live and breathe pipe standards, it's also for the average person too and is meant to be a little fun.