Perhaps, this article or this forum discussion will help. Without the data, it is hard to demonstrate how to apply to your situation. Here is an example using mtcars.
plot_ly(
mtcars,
x = mpg,
y = wt,
group = factor(cyl),
mode = "markers",
marker = list(
color = factor(mtcars$cyl,labels=c("red","purple","blue"))
)
)
