No. The history of the film is fairly well documented. There are multiple drafts of the script out there and Cinefantastique did a double issue on the film's development back in the 70s. They deliberately decided not to show the Krell and to suggest things about their alien anatomy through the set design: the low, wide doorways, the very low handrails, the staircases with the ramp groove down the center and the wide seats with the two backs, both of which suggest they had tails that dragged behind them.For all, we know we didn't get a visual on the Krell because they ran over budget...
The Id monster being invisible was a budget saving idea though, and part of how they pitched it.