In a vacuum you would have to depend on radiant heat emission to reject heat from the suit. No air or other medium to carry the heat away through conduction or convection. They might use an expendable refrigerant and vent it into space, like blowing freon on a coke can to cool it-one use only.
The gold and other materials reflect the energy from sun rather than absorb it and greate heat gain. "shiny",light materials also don't radiate heat into space as well as dark,matte finishes.