The bars on the flag are arranged to be a circle interlacing the infinity symbol, the colours are from the Olympic Flag, standing for the five continents of the world (under their definition).

Sources:

https://www.crwflags.com/fotw/flags/int-math.html (The flag/logo was upside-down on this one, so I used the second source for the logo.)

http://imo-official.org/general.aspx