Oda had already warned us about the true appearance of the Five Elders: here are his words from a year ago
The Five Elders are a council of the five highest-ranking Celestial Dragons who act as the public heads of the World Government. They essentially hold the greatest authority over the world at large as far as public knowledge is concerned, although they secretly act as figureheads for the government’s shadow leader Imu, who occupies the Empty Throne. The Five Elders’ political sway over the World Government, its subsidiary organizations, agencies, and military branches is paramount and near illimitable, including holding absolute command over Cipher Pol, the Marines, and (prior to their disbandment) the Seven Warlords of the Sea, thus controlling two of the Three Great Powers.
Political powers aside, it is currently unknown how strong each one of the Five Elders is. However, due to their clear muscles and scars, and that one of them is wielding a sword, it would appear that they have some battle experience and fighting capabilities.
The Five Elders, like Imu, are also able to transform into animalistic creatures. In these forms, they were able to take a direct hit from Sabo‘s Hiken unscathed. Alongside their shadow sovereign, the Elders were able to completely overwhelm Sabo and Cobra.
The only transformation revealed so far is that of Saturn who has eaten a Zoan-type Devil Fruit that lets him transform into a horned being with a spider-like body, including six legs. Saturn appears to have “awakened” this ability, as indicated by the ribbon of dark, flaming smoke around his shoulders and torso when he is transformed.
In his arachnoid form, Saturn is gigantic—large enough to hold Jewelry Bonney in one hand.
In 2022 Oda said in an interview with Gosho Aoyama that he did not believe he had “failed” in conceiving the Five Elders, because they had yet to show their true value. In recent chapters, indeed, we have just had the opportunity to witness this very demonstration.