Assistants or Professors at your university are often happy to give a talk about topics they are working at.
Ask companies
Most companies will send you somebody to give a talk if you are prepared for some included marketing. Try to keep it under control, but use the resources companies may offer you.
Leverage the IEEE opportunities
IEEE can help you in various ways if you need speakers for your event though the offered programs.
If you need someone to give a talk on issues internal to IEEE, such as IEEE organization structures, things IEEE can offer, or topics regarding IEEE Student Activities, the best option is to email us at r8sac@ieee.org and tell us what kind of talk you would like to have. We will then try to find someone to give a talk.
For technical speakers, societies are usually a good contact. Most of them have something like a program of distinguished speakers, or another way to find speakers.
In case you have formed a Student Branch Affinity Group or a Student Branch Chapter, you can check the sponsoring IEEE unit for targeted programs or fundings.
