Many visual effects were evaluated before deciding on the final shimmer asssoicated with the transporter beaming process. This was the most colorful, showing what ultimately was a discarded effect using multiple, different color fills for each person within a red outline being "beamed" out or in via a shimmering column.
This shot is the surface of Talos IV and the scene is the original beam down moment for Pike and landing party from the Enterprise. This effect was judged too garish and eventually the shimmer alone contained within the area occupied by the beamed object was selected. The filming of this action was done in late 1964 though the optical was likely completed a bit after.
Originally devised as a time and cost saving plot enabler, the transporter became an integral part of TOS Star Trek and beyond, entering pop culture and science fiction history.
BTW - that famous Italian company with the united colors campaign was founded in 1965, maybe around the same time as the production of this optical.