Chill well done firstly I just read a post from you dated April; seemed you were really unhappy in the last job.
I am no expert but have been both sides of the interview table and this is the perfect opportunity for you to blow your own trumpet for that is what an interview is all about. Try and work out what it is they loved on your cv and expand on that perhaps.
You should in fact be doing about 75% of the talking if I remember rightly!
Please don't let this put you off; it sounds like you have had a successful career to date and maybe the last place has dented your confidence.
If you are not a "showy" type and it sounds like you aren't, your presentation should be fine. Write down key points and try and remember them. Use visual prompts and get them in your head so you don't forget.
Practice infront of somebody or the mirror.
Be interesting, be likeable. The people will also want to assess if they can spend 8 hours a day in your company!!
A tip I use is that as they are bound to ask at the end if you have any questions, I always do a bit of research on the company and have a few clever, interesting questions which they might enjoy answering at the end such as their training programmes (go online) their sales figures or products etc.
Do dress your very most gorgeous best - imho first impressions really do count.
Finally, a firm handshake and eye contact and "thankyou for seeing me I have been looking forward to meeting you today".
Good luck, very daunting but I am sure you will be fine.