This is an activity that is appropriate for both Junior and Senior Primary.
When I introduce this activity to the children I will put the 4 pages on the board and I will ask them what they think it is. I'll ask them how it relates to the song. We'll sing the song, maybe a few times, and see if they can figure it out. If they are having trouble I may point to each block as we sing through the song. Then they will need to figure out what the colors mean. When they figure it out we'll split up the singing -- some people will sing the colors while the rest sing the non-colors. Varieties of this include me/them, children/teachers, boys/girls, sides of the room, etc. A variation I will do with Senior Primary is to put the pages on the board in random order, and tell them they will have to figure out what order they go in.
Here is mine for this song. The yellow is "I" and the blue are words relating to God and Jesus.
The Church of Jesus Christ - Melody Map
Some websites that may be helpful explaining more about Melody Maps: