Here is one
From Whitney Sews a free pattern here
The interfacing for the hat brim is this kind
From Sew Mama Sew -she tells you what needle to use and other useful information -here
You can also use felt to make the logos and either glue them on or sew them on.
I have link on the bottom to print out logos if you want to do it that way.
The shirt can be any long sleeve knit shirt that you can get at most clothing stores. You can also make your own.
Like this pajama pattern from Simplicity 1505
Here's a pattern for overall from Burda 9464
I didn't spend to much time on shoes but you could cover a pair of shoes to match your character.
From About Home there is a tutorial on how to cover shoes here
One last thing. The mustache! You can always pencil it on or could buy it. You could also make it.
I bought the dollar store knit gloves. You could also buy ones specific for the costume but as long as they are white.
Enjoy making your costume.