Leonardo DiCaprio -- I'm 40! More Models, Please

Leonardo DiCaprio turns 40 better than you do ... 'cause when he does it ... he's surrounded by hot models and A-list celebs in a super-exclusive club.

According to sources inside the party ... Leo shutdown SoHo House in West Hollywood Tuesday night. His pals Tyrese, Adam Levine, Russell Simmons, and Robin Thicke were there -- but more importantly ... there was a ton of window dressing.

We're told it was about "80% models" inside the event ... which, for Leo, adds up to a very happy birthday.