I think the site is reporting M2 for each of the currencies, which includes much more than just the bills + coins. E.g. the value of all USD coins + bills is "only" $2.1 trillion [1] vs. an M2 that's 10x larger. The 60% of all USD are held overseas statistic only applies to coins + bills and not M2 [2].
An explanation could be that people in Chinese save more and keep more of their savings in banks, compared to Americans?