In my opinion, one aspect I observed that is important is that many new entrants to Perl would likely find it sort of confusing at first sight, especially for those who are used to have everything checked at compile time such as Java and C++, with a much more structured syntax compared with more dynamic languages such as Perl.
It's sort of easy to find a book or online resources to learn a programming language, so I think your emphasis in a knowledge sharing session is best placed on something that is not as directly acquired from those resources. Experience is the key. Do show them what Perl can do, and why that kind of flexibility is good.
Another thing I think you may consider is that you can be more of a motivator than a teacher, and try to help them learn on their own. There are a lot of details in the perldoc itself and if one can understand how to read them then it will be the most important resource they should go to when they have questions. If you know the stuff, then some guidance will be helpful, say the Perl OOP is not easily accepted by most Java/C++ programmers and they likely need some support there.