Since the production for the last supercars takes generally 2 years, I suspect that as we are discussing the Lamborghini right now talks are already underway for the next one. And a clue for the next supercar lies in the surge of a certain color.
2015: 42038 in Orange
2016: 42048 and 42052 in Orange
2017: 42070 in Dark Azure
2018: 42074 and 42077 in Dark Azure, and 42079 in Dark Blue
2019: Nothing in Lime though
2020: 42102, 42103, 42105 in Lime
This year we see the surge of a new color: Light Orange/Flame Orange (42099's color). So the next car may have this color. However, any speculation is too early at this point because a supercar's dominant color only surges in the year or one year before the year that supercar is released.