I was trying to use ggplot to make a plot with following needs.
- Use points to specify subjects.
- Use color to specify models. I have 6 models, so each subject should appear 6 times on the plot.
The plot is expected to look something like this:

I can use color to specify models but cannot find a way to specify subjects as point shapes.
Example data
structure(list(subject = c("S1", "S8", "S3", "S9"), alphamean = c(0.224104019995071,
0.195354811041001, 0.5675953626788, 0.491972414993715), lambdamean = c(0.35985383877637,
0.268124038994992, 0.92122181060701, 0.43561465728315), model = c("a",
"b", "c", "d")), row.names = c(NA, -4L), class = c("data.table",
"data.frame"))
My attempts
data %>%
ggplot(aes(x = alphamean, y = lambdamean)) +
geom_point(aes(color=model,shape=subject)) +
scale_shape_manual(values = paste0('S',1:40))
