A method for manufacturing a symbol on an exterior of an electronic device is provided. The method includes preparing a support layer, preparing a nanograting layer on the support layer, the nanograting layer including a first nanograting area corresponding to a preset symbol and a second nanograting area corresponding to an area other than the preset symbol, wherein each of the first nanograting area and the second nanograting area includes three-dimensional (3D) nanostructures and a pitch between the 3D nanostructures arranged in the first nanograting area is different from a pitch between the 3D nanostructures arranged in the second nanograting area.