The 70% includes hispanic, which have traditionally been considered white, and only are now considered a separate group because it benefits democrats. But if you go by that split, Texas is 45% white, 37% hispanic, 11% Black, 4% Asian, and some misc and rounding error make up the last few points.
It gets very confusing
Federal policy defines “Hispanic” not as a race, but as an ethnicity. And it prescribes that Hispanics can in fact be of any race.