I did at least half of the work, I am not cited in the presentations
It definitely sucks when you feel like you're not getting credit for your work, and in applied math, it is certainly not standard practice to omit mention of PhD students' contributions.  In fact, I've seen many presentations where professors and industry leaders show group pictures of their entire lab, and they're proud of the team effort.

However, passive aggression is almost never effective at helping you achieve what you want.

You seem to be on better footing with your supervisor than with his colleague, so I would start there.  Once you've cooled off a bit, schedule a meeting with him and mention how you've noticed your name is absent from presentations on your work.  Be honest (and respectful) about how this hurts you, and leave room for your advisor to explain.  It could just be an honest oversight, it may be intentional-- the fact is, you don't have anything but speculation until he explains.  Mention that you've noticed the same happens with his colleague's presentations, and ask if he could talk to the guy about it.  Again, try not to assume the worst.  There isn't any real motivation for omitting someone's name when they've made serious contributions, especially in industry, where large author counts are the norm and papers don't matter nearly as much as they do in academia.