Use a basic tan work coverall. Most of the Dharma people wore this color, but dark blue is another option since those were worn by the motor pool and work staff members.
Open an appropriate Dharma Initiative logo copy in a photo editing program. Resize it until it is about the size of a shirt pocket.
Print the logo on inkjet printable fabric. Cut the logo out of the sheet of fabric.
Iron or stitch the logo on the upper left-hand corner of the jumpsuit.