This hot swimsuit that Darj is wearing comes from a set of animal-themed swimsuit outfits in the Great Tankery Operation game. Look here for other outfits in the set: https://twitter.com/garupan_app/status/1283282648249462785 (the animal being referenced is more obvious on some than on others). In this case, Darjeeling's swimsuit is inspired by the European Robin, which has an orange area on the front that is often surrounded by a region of light blue feathers. In the official art it is easier to see that the pattern on the shawl is supposed to be feathers, going with the bird theme.