It depends on who you are talking to. Any explanation has to be pitched at the right level. My explanation to a chemical engineer would be different to my explanation to a mathematician or a finance manager.
The best approach is to relate it to something in the expertise of the person you are talking to. As a rule sequencing is a fairly universal problem, so try to find something the person knows about where you say "first do X, then do Y". Then explain how ordinary programming languages have a problem with that; if you say "do X, then do Y" to a computer it does X and Y immediately without waiting for further input, but it can't do Z in the meantime for someone else; the computer's idea of "and then do" is different from yours. So programmers have to write their programs differently from the way that you (the expert) would explain it. This creates a gap between what you say and what the program says. It costs time and money to cross that gap.
Monads let you put your version of "and then do" into the computer, so you can say "do X and then do Y", and the programmer can write "do {x ; y}", and it means what you mean.
