Alan Shepard’s Mercury MR-3 pressure suit looks much different than suits from the later NASA missions. This is because they were created for different functions and purposes. Eight years before Neil Armstrong made the first step on the Moon, Alan Shepard became the first American into space.
Shepard’s suit had no liquid cooling layer, only air.
Communications were integrated into his helmet, not the main suit.
Essentially, Shepard put on a jumpsuit and helmet much in the same way pilots had been doing for decades before.
This was okay because Shepard never needed to leave his spacecraft and in total spent approximately 15 minutes in space. There's still time to help us reboot Shepard's spacesuit.
Shepard's pressure suit is not on display at the National Air and Space Museum. It is either on loan or in storage.